Present practice in preparation and finishing of approximal fillings typically requires use of a matrix band to supportively gird a crown wherein the filling is to be performed. The matrix is tautly engaged in supporting contact with the tooth by means of a wedge fitted through the embrasures to marginally space approximal teeth apart and maintain pressure against a matrix there in situ.
Wedges seen in the current state of the art are typically solid, semi-rigid, polymeric elongate bodies that are manually forced between approximal teeth (for example, Eames, U.S. Pat. No. 3,815,243; Gores, U.S. Pat. No. 3,890,714; Harsany, U.S. Pat. No. 4,337,041; among others). While this method is effective, it does present certain issues. The wedge itself must be forcibly introduced through the embrasures to maintain position, and is essentially pressured in contact with an appropriately situated matrix band by virtue of its solid body forced between the teeth. Fitting of the wedge may be difficult, then, uncomfortable, and maintenance of the position problematic. Additionally, taut contact with the associated matrix band may likewise be variable, depending on which approximal teeth the wedge is fitted between and the variance of interdental and interproximal spaces evidenced between patients.
Traditional wedges also typically exhibit a constant gradient in cross-section wherein the width reduces consistently towards a tip. The narrowest portion of these wedges, then, is distally and endwise disposed. Position of such wedges through the interproximal space between approximal teeth, therefore, leaves a narrower portion of the wedge exposed in one embrasure versus the other, whereby pressure exerted by the wedge against an approximally fitted matrix band is thereby inconstant.
What is needed is an interdental laterally expansive wedge that is fittable in position between approximal teeth and thence expansible by introduction of a fluid compressibly forcible thereinto, to space apart a pair of basal ridges into consistent contact with neighboring teeth and any matrix band situated appropriately for approximal filling preparation and finishing. This lateral expansion is effective to maintain even and uniform contact with an approximal matrix band when a furled bottom side of the present interdental laterally expansive wedge is moved between a first position and an expanded position.
Inflatable wedge-like apparatuses are seen in the art, but present additional problems the instant invention is devised to overcome. For example, the interdental balloon taught by Suhonen (U.S. Pat. No. 6,007,334) is flexible and expansive, essentially a stretchable polymeric balloon that increases in volume simultaneously along all radii by act of inflation, whereby bulges and ballooning around sulcuses and embrasures present problems of deformation and application of inconsistent pressure between and around approximal teeth. Such ballooning may force the matrix band to intrude into the cavosurface into the cavity proper, and thus misalign a finished filling.
The inflatable dental device taught by Thoreson (U.S. Pat. No. 6,439,886) attempts to enable more lateral expansion, and even obviate use of a separate matrix band and wedge altogether. Thoreson teaches a plurality of flexible walls having fused inner areas by which introduction of fluid enables forcible expansion of at least one chamber to inflate the plurality of walls apart, thus effecting more lateral expansion. However, the flexibility Thoreson teaches enables deformation of the most exterior walls to intrude into the cavity, actually invading the cavosurface the band is meant to immure. This is particularly problematic when he device is used absent any matrix band, as Thoreson is given to teach.
The present invention, however, overcomes these and other problems by enabling an interdental laterally expansive wedge that includes a prismatic wedge having a non-expansive apical ridge disposed longitudinally between a distal tip and a proximal interconnect wherein forcible introduction of a fluid into the wedge effects expansion of a furled bottom side between a first position and an expanded position, whereby each of a pair of basal ridges is laterally separated apart around an angle of expansion delimited at the apical ridge, and even, uniform, and consistent pressure is applied to contacted surfaces without ballooning or appreciable deformation of the wedge into and around sulcluses or embrasures, and without invasion over the cavosurface within the interproximal space.